Electrochemical energy conversion devices such as fuel cells, electrolyzes, and flow batteries often rely on a polymer electrolyte separator to conduct ions while being electrically insulating and impermeable to reactants (i.e. H2 and O2 in the case of a fuel cell). The typical polymer electrolyte consists of a hydrophobic phase for mechanical support and an ion-conducing, hydrophilic phase. The two phases often separate on the nanometer scale where investigation with small angle x-ray scattering (SAXS) is able to provide meaningful insight into the morphology. Our group has fabricated an environmental chamber, which, in conjunction with a synchrotron, allows for collection of SAXS data under different temperatures and humidities. The insight into the polymer morphology through SAXS studies often plays a key role in understanding the performance of new materials. Our group has been developing new polymer electrolytes with heteropoly acid (HPA) moieties for use in fuel cells under drier conditions. Using SAXS we are able to better understand the relationship between morphology and transport under low humidity. We have identified that materials exhibiting HPA clustering have inhibited proton conductivity. Our newest HPA/polymer platform exhibits outstanding chemical durability and performance under humidified conditions, but suffers from clustering. Efforts to mitigate the clustering and improve overall performance will be discussed.

Heteropoly acid polymer electrolyte development via small angle x-ray scattering under fuel cell relevant conditions

255th National Meeting (2018)

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